Control mechanism for the automatically actuated clutch of an internal combustion engine



May 2, 1961 F. J. VON BOMHARD 2,982,383

CONTROL MECHANISM FOR THE AUTOMATICALLY ACTUATED CLUTCH OF AN INTERNAL COMBUSTION ENGINE Filed April 5, 1958 3 Sheets-Sheet l 0 m. w w WW Mm W6 T I A WW Hm a W w. mm W klwii y 1961 F. J. VON BOMHARD 2,982,383

CONTROL MECHANISM FOR THE AUTOMATICALLY ACTUATED CLUTCH OF AN INTERNAL COMBUSTION ENGINE Filed April 3, 1956 3 Sheets-Sheet 2 ATTORNEYS.

y 1961 F. J VON BOMHARD 2,982,383

CONTROL MECHANISM FOR THE AUTOMATICALLY ACTUATED CLUTCH OF AN INTERNAL COMBUSTION ENGINE Filed April 3, 1958 5 Sheets-Sheet 5 BY A ' ATTORNEYS.

United States Patent CONTROL MECHANISM FOR THE AUTOMATI- CALLY ACTUATED CLUTCH OF AN INTERNAL COMBUSTION ENGINE Frans Josef von Bomhard, Schweinfurt (Main), Germany, assignor to Fichtel & Sachs A.G., 'Schweinfurt (Main), Germany, a corporation of Germany Filed Apr. 3, 1958, Set. No. 726,274 Claims priority, application Germany Sept. 29, 1954 5 Claims. (Cl. 192-35 The present invention relates to a mechanism for the control of the coupling or engaging operation of automatically actuated clutches. More particularly, it relates to a control mechanism for the automatically actuated clutches of internal combustion engines for driving self-propelled vehicles and the like, said mechanism serving to match or correlate the coupling torque with the' load.

This application is a continuation-in-part of my copending application, Serial No. 536,929, -filed September 27, 1955, now abandoned.

With automatically actuated clutches, the coupling torque is generally limited initially to such an extent that matching of the speed of rotation of the engine or motor to the rotational speed of the driven shaft which carries the load'is efiected gradually and without jerking or grabbing. This is accomplished by means of special clutch controlling mechanisms which in a pneumatic or hydraulic operation eifect a gradual equalization of the pressure whereas in an electromagnetically actuated clutch the desired result is .obtained by a step-wise shunting out of resistors. 1

In order to be able to transfer the increased motor torque produced after a gear shifting operation by feeding gas to the engine, it has been proposed to connect the clutch controlling mechanism with the throttle shaft or to the gas linkage of the fuel feeding system so as to thereby eifect a residual equalization of the pressure in pneumatically or hydraulically actuated clutches or to eliect the shunting out of resistors in electromagnetically actuated clutches. The operative connection between the clutch control mechanism andthrottle shaft or gas linkage was effected by a mechanical connection of the controlling means to the control valve or the resistor switches. Such constructions whil'e constituting an advance over former structures, still sufier from the disadvantage that torque to be controlled independently of the rotational.

speed of the engine.

It'is another object of the invention to provide a control system which is adaptable to a variety ofditfer'ent operating conditions of the vehicle.

A further object of the invention is to eliminate in large part the numerous mechanical connections heretofore required for controlling the coupling torque, thereby permitting a wide choice in the arrangement and disice of the fuel'feed of an internal combustion engine.

Yet another object of the invention is to provide a smooth acting controlling mechanism, thereby eliminating jerking or stalling of the engine when feeding gas after completion of a gear shifting operation.

In accordance withthe present invention, it has been found that upon controlling engagement of the automatically actuated clutch by the pressure in the suction line of the fuel supply, the coupling torque will remain largely independent of the rotational speed of the motor. Moreover, the coupling torque will be approximately directly proportional to the prevailing pressure in the suction line, i.e., the ratio betweenthe coupling torque and the suction line pressure will be approximately linearand independent of the rotational speed of the engine.

- It is a salient object of the invention to provide clutch controlling mechanism,automati cally effective in response to the initial movement of the gear shift lever toward neutral to completelydisenga-ge the clutch and to maintain the clutch fully disengaged until the new gear-connections are fully established, and then automatically to cause the clutch members to be smoothly re-engaged while limiting and controlling the coupling torque in accordance with, and in response to, the pressure in the suction line of the engine.

Elimination of the throttle as the connecting or controlling mechanism simplifies the mechanical arrangement of elements and permits a wide latitude in the disposition of the control elements of the novel system.

Furthermore, the control operation may be suitably retarded so that jerking, which might otherwise occur upon the sudden feeding of fuel, will be avoided, thereby providing a smooth acceleration.

The invention will now be described more fully with reference to the accompanyingdrawing, wherein:

Figure 1 is a lateral elevation of an automobile engine having the novel mechanism of the present invention incorporated therein for the control of a clutch which is automatically actuated by pneumatic means;

Figure 2 is a sectional view of a portion of the control mechanism of Fig. l; a

- Figure 3 is a sectonal view of a portion of a modified mechanism for the control of a clutch which is automatically actuated by electromagnetic means; and

Figure 4 is a' sectional view of a portion of a further embodiment of a control mecham'sm for an electromagnetically actuated clutch.

Fig. 5 is a lateral elevation of an automobile engine having the'modified mechanism suitable for control by the control device of Fig. 3.

' Referring now more particularly to the drawing, in Fig. 1 there is. shown an internal combustion engine designated generally as 11 which is coupled in conventional manner with a load such as the traction wheels of a vehicle by means of a clutch 12 which is enclosed in The clutch desirably comprises a- Actuation of the clutch is controlled by a disengaging lever13 which at its upper end is pivotally connected witha linkage 14. The linkage 14is arranged for displacement by power operable means and carries at its end remote: from lever 13 a piston head 15 which operates in a cylinder 16 serving as a servomotor unit for control-- ling actuation of the clutch.

1 A duct or line 17 leads from the servornotor unit to a housing 18 which contains a reduction valve 19 (Fig;v

Patented May 2, 1 961 2) .anda control valve 20. Adjacent the reductionvalve 19, the housing 18 includes a chamber 21 and a diaphragm 22 separating the chamber 21 from the remainder ofthe housing, viz.,, zone 23, and space 24. Theuchamber 21 isin communication with the intake manifold or suction line-.25 of the engine by means of pipe 26. space.24 of housing18 is also in communication with the. suctionline 25 by means of pipe 27 whch enters the housing 18 adjacent control valve 20.

In Fig. 2 housing18; and its associated elements are shown on anenlarged scale, in a position wherein the clutch is fully engaged. Within housing18 the valve 20' is providedwith an elongated stem 28, the enlarged end 29 of which functions as-a core for the solenoid winding 30. A compression spring 31 supported by the inner wall of space 24 surrounds the stem 28 and bears against the head of valve 20, thereby urging it toward the left into a position, wherein it closes 01f pipe 27 from communication with line 17. It will be noted that stem 28,

extends through an aperture32 which afiords communication between line 17 and pressure-restoration space 24. The aperture 32'is of such diameter that it is completely closed 011 by the head of valve 20 when the core 29 is withdrawn to the right by solenoid winding 30.

The reduction valve 19 is urged to the left in Fig. 2;

by a pressure regulating spring 33 acting on one side thereof, the force of said spring being adjustable by means of screw 34provided with a manipulating head 35 extending outwardly from space 24. The zone 23, which is in communication with the atmosphere through port 36, is located on the other side of valve 19 and is separated from chamber 21 to the left by diaphragm 22. Diaphragm 22 is provided with a projection or rod 37 extending into zone 23, but spaced from valve 19in the position of the elements shown in Fig. 2.

A set screw 38 operated by a manipulating knob 39 extends into chamber 21 and determines the pressure of a spring 40 against daphragm 22, and thus the disposition of projection 37 relative to valve 19.-

In use, the gear shifting lever 40a of the vehicle is operated in conventional maner to effect a change of gears. Operation of the gear shifting lever energizes a solenoid winding 30 in the manner described in US. Patent Application Serial No. 490,360 filed on February 24, 1955, now Patent No. 2,848,080 issued to Richard Binder on August 19, 1958. Briefly, the lever 40a is caused to carry an insulated movable contact plate 40b which is curved and which has substantial width and height. The contact 40b escapes engagement with one or the other of 'the two fixed contacts 40c and 40d when the gear shift lever is in anyone of the usual driving positions, but in the initial movement of the lever toward neutral the contact 40b is moved'into position to connect 40c electrically with 40d. This relationship is maintained until after the new gear ratio connection has been fully established. The finalmovement of the lever 40a into any one of its driving positions breaks the connection through 40b between 400 and 40d.

Engagement of contact 4% simultaneously with 400.

and40d establishes a circuit from a source of electrical potential S through a conductor 40s, the solenoid winding 30, a conductor 40], contacts 40d, 40b and 400, and a conductor 40g to ground, the second terminal of source S being also connected to ground through a conductor 40h.

Energization of the winding 30 causes the core 29 and.

stem 28 to be displaced to the right so that valve 20 moves away from pipe 27 and closes 01f aperture 32. As a result, the clutch disengaging line 17 is no longer in communication with space 24 but instead is in communication with the intake manifold 25 through pipe 27.

The reduced pressure prevailing in servomotor line 17 causes piston 15 to be displaced to the left in servomotor unit 16, carrying linkage 14 along. Lever 13. is therefore pivoted counterclockwise and the clutch 12 is thereby disengaged.

The,

Upon completion of the gear shifting operation, solenoid 30 is de-energized and the value 20 is returned to the position shown in Fig. 2 wherein the servomotor line 17 is in communication with space 24 through aperture 32 and is no longer in communication with the intake manifold 25 of the vehicle. The ensuing pressure drop in space 24causes opening of the pressure regulating valve 19' between the space 24 and the zone 23 which is in communication with the atmosphere through port 36. Valve 19 remains open until the pressure differential determined by the compression spring 33 is attained. The attained pressure in space 24 and line 17 being higher than that previously in line 17, the piston 15 is now displaced to the right and thus the clutch is only partially engaged to transfer a low maximum torque.

If gas is fed in large amounts, the pressure in the intake manifold 25 will be increased (the suction will be diminished) and as a result the absolute pressure within chamber 21 will also increase. The increased pressure has no effect on the control valve 20 which is maintained by its spring 31 in its position closing off pipe 27. As the absolute pressure within chamber 21 increases the diaphragm 22 is displaced to the right carrying projection 37 along until the latter displaces valve 19 to the right against the pressure of spring 33. Consequently, the atmosphere is then in communication with space 24 and the pressure within line 17 is further increased until the piston 15 is displaced to its maximum right-hand position and the lever 13 is pivoted to its maximum extent in clockwise direction. The clutch 12 is then fully engaged.

The extent of engagement of the clutch and accordingly the maximum torque of the engine which can be delivered to the wheels is thus controlled in dependence upon the pressure prevailing in the intake manifold 25 of the internal combustion engine.

Figs. 3 and 5 relate to a modified mechanism suitable for controlling an electromagnetically actuated clutch,

as opposed to the pneumatically actuated clutch of Figs. 1 and 2.

The clutch of Figures 3 and 5 may be generally like the clutch of Figure 1, but it is spring biased toward the disengaged condition and is solenoid actuated into an engaged condition. carries two insulated contact plates 14% of substantial area at its opposite sides. The conductor 140i is con nected to two fixed contacts 140d which are engageable with the respective plates 140b, while the conductor 140k is connected to two fixed contacts 1400 engageable with the respective plates 1401;. The arrangement is such that in any driving position of the gear shift lever 140a one of the plates 14Gb will connect one pair of contacts 1400, 140d to one another, thereby completing an energizing circuit through the winding of a solenoid 118 for holding the clutch members engaged. The circuit may be traced from one terminal of source S through conductor e, solenoid winding 130, conductor 140k, a resistance device 140m, a conductor 140f, one of the plates 140b and conductor 14% to ground, the opposite terminal of the battery being connected to ground through a conductor 14011. As has been noted, any movement of the lever 140a toward a non-driving position breaks the circuit, de-energizes the solenoid 130, and causes the clutch to be disengaged. Upon re-establishment of the circuit the coupling torque is limited by the resistance device 140m.

In Figs. 3 and 5, the projection or rod 137 on the suction line controlled diaphragm 122 is provided with an insulated contact member 141 connected to conductor The gear shift lever 14011 id 1) actly selectable characteristic, series resistors of the device 140m so as to increase the maximum transferable coupling torque in the desired manner as the pressure in t the suction line is increased.

- plunger head 50 at its other side carries a rod 53 which passes through an aperture 54 in the right hand end of the cylinder, the rod 53 having secured thereto a lead 54'. connected with a movable contact 55 urged outwardly by spring 56. Contacts 57, 58, 59 and 60 are adapted to cooperate with contact 55 to control. an electromagnetically actuated clutch, as described in connection with Figs. 3 and 5.

As gas is fed to the engine, the suction is diminished and the absolute pressure prevailing in line 49 is increased, thereby displacing the plunger head 50 to the right under the action of spring 52. As the plunger head 50 moves, the rod 53 and contact 55 are carried along to the position shown in Fig. 4, so that successive engagementis made with contacts 57 through 60. The current to the electromagnetic means controlling the clutch is thereby successively increased and the engagement of the clutch is accordingly progressively increased together with the transmitted torque.

A restricted opening or orifice 61 is provided between line 49 and cylinder 48 so that the pressure changes within the cylinder lag slightly behind the pressure changes within the intake manifold of the engine. As

a result there is a retardation of the controlling effect so that even sudden feeding of gas will produce a gradual and smooth engagement of the clutch. -In'place of an orifice such as 61, the same retardation effect can be achieved by varying the dimensioning. of the line 49 so as to provide a flow passage of reduced cross-section.

In all of these embodiments it can. be seen that engagement of the clutch, whether the latter is actuated by pneumatic or electromagnetic means, is controlled in dependence upon the pressure prevailing in the intake manisary, is also simple and is -facilitated by the fact that clutch, control means connected to said power operable means and responsive to gear shifting displacement of said gear shift lever for causing disengagement of said clutch during said displacement and re-engagement thereof after completion ofsaid displacement, and pressure responsive means connected to said intake manifold and acting on said control means, said pressure responsive means initially causing said control means to produce only partial re-engagement of said clutch by said power operable means after completion of said displacement of said gear shift lever, complete re-engagement of said clutch by said power operable means being caused to occur by action. of said pressure responsive means on said control means in response to an increase in pressure in said'intake manifold subsequent to said completion of said displacement.

2. A system according to claim 1, in which said power operable means consists of a suction operated servomotor and wherein said control means is a control valve connected for actuation by said displacement of said gear shift lever and arranged to connect said servomotor to said intake manifold during said displacement for disengaging said clutch, and wherein said pressure responsive means is connected to said control valve, said control means comprising a pressure regulating valve through which said servomotor is connected to the atmo-sphere "by said control valve after said completion of I said displacement for causing said partial re-engagement,

said pressure responsive means further comprising pressure actuated means connected to said intake manifold disposed to cause complete opening of said pressure regulating valve in response to said increase in pressure in said intake manifold.

3. A system according to claim 2, further comprising.

trol valve is an electromagnetic valvehaving an operat ing winding for the actuation thereof, said system including an energizing circuit for said operating Winding and switch means included in said energizing crcuit, said switch means being actuated by said displacement of said gear shift lever.

. -5. A system according to claim 1, wherein said power operable means is ,asolenoid, said system including an energizing circuit for said solenoid, and in which said control means comprises switch means included in said energizing circuit and actuated by said displacement of said gear shiftelever, and in which said pressure responthe mechanism may be disposed in readily accessible H places without extensive mechanical couplings.

Various changes and modifications may be made with out departing from the spirit and scope of. the present invention as defined in the annexed claims. What I claim is:

1. A propulsion system for a motor vehicle comprising, 7

an internal combustion enginehaving an intake manifold,

a selectively, disengageable and progressively 're-engage- 'ableclutch, a gearshift lever, power operable means consive means comprisesrheostat means included in said energizing circuit for varying the current flow in said solenoid. v V V References Cited in the file of this patent UNITED STATES PATENTS 1,806,158 Giger May 19, 1931 r 2,049,738 Hill et a1 Aug..4, 1936 ',2,144,022 ,Kliesrath Jan. 17, 1939 2,317,216 Paton Apr. 20, 1943 v n Bomhard June 14,1960 

